Captcha is a type of challenge-response test used in computing environments to attempt to ensure an entered response is generated by a person and not an automated response generated and entered by a computing device. If these automated responses were not identified and blocked by Captcha, the quality of the service being requested could degrade.
One example of Captcha operates by sending an image with a randomly generated string and added noise which the requesting computing device must key into a field. The noise added to the randomly generated string is designed to prevent automated computing systems from identifying and entering the displayed string. Unfortunately, the added noise can render the Captcha image difficult for the person at the requesting computing device to recognize and correctly enter. Additionally, improving OCR and other image recognition techniques are enabling automated system to identify and enter the string.
Another example of Captcha requires the user at the requesting client computing device to perform and enter the results of certain mathematical operations, although the completion of other types of analytic operations could be required. However, as with the previously described example, automated computing devices are becoming more sophisticated and often are able to scan, execute and correctly enter results for the requested operation.